package top.kaoshanji.p1ch04a;

import org.apache.hc.core5.http.ContentType;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.nio.charset.StandardCharsets;
import java.util.Enumeration;

/**
 * 代码清单-p1ch04a-128页a：查询首部
 * URL访问地址：/headerSnoop
 * @author kaoshanji
 * ^_^
 * create time 2025/4/3 20:02
 */
public class HeaderSnoop extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // 设置请求对象的编码
        req.setCharacterEncoding(StandardCharsets.UTF_8.name());

        // 设置响应对象的编码和内容格式
        resp.setContentType(ContentType.TEXT_PLAIN.toString());
        PrintWriter out = resp.getWriter();

        out.println("Request Headers:");
        out.println();
        Enumeration<String> names = req.getHeaderNames();
        while (names.hasMoreElements()) {
            String name = names.nextElement();
            Enumeration<String> values = req.getHeaders(name); // 支持多值
            if (values != null) {
                while (values.hasMoreElements()) {
                    String value = values.nextElement();
                    out.println(name + ": " + value);
                }
            }
        }
    }

}
